<!-- 
    VUE中如何监测数据的原理_对象;

    =>  拿到data 
    =>  加工data(_data) 
    =>  把data中的属性都放到vm上,并添加getter和setter;
 -->
 <!DOCTYPE html>
 <html lang="en">
 <head>
     <meta charset="UTF-8">
     <meta http-equiv="X-UA-Compatible" content="IE=edge">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>Document</title>
    <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
 </head>
 <body>
    <div id="root">
        <h2>name: {{name}}</h2>
    </div>
 </body>
 <script>
     const vm = new Vue({
         el: "#root",
         data:{
             name: "Jingwen"
         }
     })
 </script>
 </html>